mt-daapd is a program which acts as an iTunes (DAAP) server for Linux
and other POSIX unixes.

Some random features:

 o Can advertise shoutcast streams.
 o Is web-configurable and manageable.
 o Supports dynamic playlists, like iTunes "Smart" playlists.
 o Now supports iTunes 5!

Things to watch out for:

The database is indexed by inode so all music must be on the same
filesystem.
